Cover structure with vent

ABSTRACT

A cover structure with a vent is provided which includes a cooling fan, and a cover having a vent portion provided with a plurality of air-through holes through which air forced by the cooling fan escapes. The vent portion is formed spaced away from the cooling fan by a distance of about 6-10 mm. The distance of about 6-10 mm between the cooling fan and the over reduces the fluid flow noise.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a cover structure with a vent portionpermitting the escape and intake of a fluid such as air, gas, and thelike, and more particularly, to a cover structure that is used in avariety of electronic systems such as a plasma display panel (PDP) TV, aliquid crystal display (LCD) projector, and the like, the coverstructure being provided with a vent portion that can minimize noisecaused by fluid flow forced by a cooling fan.

2. Background of the Prior Art

Generally, electronic display systems such as a PDP TV and a LCDprojector generate a large amount of heat in the course of theiroperations.

For example, the PDP TV generates a large amount of heat by the emissionof ultraviolet rays of plasma. Such heat is generally discharged out ofthe system by, for example, a cooling fan. If the heat is notsufficiently discharged, the system may not be stably operated, and itmay even malfunction. Particularly, as the PDP system generatesrelatively high heat compared to other systems, it requires a largecooling capacity compared to other systems.

In addition, in case of the LCD projector, in order to project an imageformed on the LCD on a large-sized screen, a lamp of the LCD projectorshould be increased in its brightness.

However, when the brightness of the lamp is increased, an internaltemperature of an optical engine is also increased, therebydeteriorating the functions of the projector. For example, the liquidcrystal may be boiled or the polarizer may be burned.

To solve these problems, a cooling fan is installed in the system toforcedly discharge the heat out of the system.

However, the cooling fan causes noise. The noise can be classified intothree types of noise: cooling fan operating noise, a vibration noisecaused by a cooling fan support, and fluid flow noise caused by the flowof fluid forced by the cooling fan.

Many designs have been proposed to properly deal with the cooling fanoperating noise and the vibration noise, but no design has been proposedfor the fluid flow noise.

FIG. 1 shows a conventional cover structure with a cooling fan.

As shown in the drawing, a cover structure comprises a back cover 10formed on a rear wall of a flat display, as an example, and a coolingfan 20 disposed spaced away from the back cover 10 by a predetermineddistance. The back cover 10 is provided with a vent portion 11 throughwhich air comes in or goes out.

At this point, the distance “a” between the cooling fan 20 and the backcover 10 is designed to be as small as possible so as not to deterioratethe slim characteristic of the flat display.

However, since the fluid flow noise is not considered when designing thedistance “a”, severe fluid flow noise is generated when the cooling fan20 operates.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to a cover structure witha vent that substantially obviates one or more problems due tolimitations and disadvantages of the related art.

An object of the present invention is to provide a cover structure witha vent portion that is designed to minimize fluid flow noise when acooling fan operates.

Another object of the present invention is to provide a back coverstructure with a vent portion that can minimize fluid flow noise byproperly designing the cooling fan and the back cover.

To achieve these objects and other advantages and in accordance with thepurpose of the invention, as embodied and broadly described herein,there is provided a cover structure with a vent. The cover structureincludes: a cooling fan for discharging air heated by internal parts ofa system; and a cover having a vent portion provided with a plurality ofair-through holes through which the air forced by the cooling fan isescaped, the vent portion formed corresponding to the cooling fan andbeing spaced away from a blade of the cooling fan by a distance of about6-10 mm.

In an aspect of the present invention, there is provided a coverstructure with a vent, including a cooling fan for discharging airheated by internal parts of a-system; and a cover having a vent portionprovided with a plurality of air-through holes through which the airforced by the cooling fan is escaped, the vent portion formedcorresponding to the cooling fan and being spaced away from the coolingfan by a distance of about 6-10 mm.

In another aspect of the present invention, there is provided a coverstructure with a vent, including a cooling fan; and a cover having avent portion provided with a plurality of air-through holes throughwhich air forced by the cooling fan is escaped, the vent portion formedbeing spaced away from the cooling fan by a distance of about 6-10 mm.

Therefore, the cover structure of the present invention is designed toreduce the fluid flow noise caused by the operation of the cooling fan,thereby preventing malfunctions of the system where the cover structureis employed.

In addition, the appearance of the back cover is improved, providing agood impression to the user.

It is to be understood that both the foregoing general description andthe following detailed description of the present invention areexemplary and explanatory and are intended to provide furtherexplanation of the present invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the present invention and are incorporated in andconstitute a part of this application, illustrate embodiment(s) of thepresent invention and together with the description serve to explain theprinciple of the present invention. In the drawings:

FIG. 1 is a schematic view of a conventional cover structure with acooling fan;

FIG. 2 is a schematic view of a back cover structure facing a coolingfan according to a first embodiment of the present invention;

FIG. 3 is a graph illustrating a system resistance curve in accordancewith the operation of a cooling fan;

FIG. 4 is a graph illustrating fluid flow noise in accordance with thevariation of a distance between a cooling fan and a back cover;

FIG. 5 is a graph illustrating fluid flow noise of a variety of fanswith different specifications in accordance with the variation of adistance between a cooling fan and a back cover;

FIG. 6 is a schematic view of a back cover structure according to asecond embodiment of the present invention;

FIG. 7 is a schematic view of a back cover structure according to athird embodiment of the present invention;

FIG. 8 is a schematic view of a back cover structure according to afourth embodiment of the present invention; and

FIG. 9 is a schematic view of a back cover structure according to afifth embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to a preferred embodiment of thepresent invention with reference to the accompanying drawings.

FIG. 2 shows a cover structure with a vent portion according to a firstembodiment of the present invention.

As shown in the drawing, a cover structure comprises a cooling fan 120for creating a fluid (air) current, and a flat cover 110 disposed facingthe cooling fan 120 with a gap “b” of about 6 mm and provided with avent portion having a plurality of fluid-through holes 111. Although notillustrated in the drawing, the heat generating parts are located on aleft side of the cooling fan 120 in the drawing.

As the cooling fan 120 and the cover 110 are provided as a back cover ofa system such as a PDP TV and an LCD projector, the cover 110 will bereferred to as “back cover” hereinafter. However, the present inventionis not limited to this. That is, the cover 110 can be provided at avariety of locations in accordance with the applications where it isemployed.

A method for determining the gap “b” between the cooling fan 120 and theback cover 110 will be described hereinafter.

A caloric value generated from the systems such as the PDP TV, the LCDprojector and the like is first calculated to select the cooling fan 120having a proper fluid flow rate.

Then, the cooling fan 120 is installed facing the back cover 110provided with the vent portion having the fluid-through holes 111.

When the cooling fan 120 is driven, fluid in the system starts flowing.As the fluid flows, fluid flow resistance is generated, which isestimated as fluid flow noise incurred in the system. Therefore, it ispossible to find a proper operating point of the cooling fan withreference to the fluid flow noise.

The estimation method of the fluid flow noise will be describedhereinafter in conjunction with the accompanying drawings.

FIG. 3 shows a graph illustrating the fluid flow resistance of thesystem where the cooling fan is employed.

In the graph of FIG. 3, the X-axis indicates cubic feet per minute(CFM), and the Y-axis denotes a static pressure rise (SP).

In addition, there are shown a fan characteristic curve 31, aperformance chart 32, and a system resistance curve which passes througha performance point 34 where the fan characteristic curve 31 meets theperformance chart 32.

Since a variety of fan characteristic curves 31 with respect to specificcooling fans are well known in the art, when the cooling fan is selectedin accordance with the desire fluid flow rate, the fan characteristiccurve 31 can be easily obtained.

In addition, by measuring an actual flow incurred by the cooling fan,the performance chart 32 and the performance point 34 can also be easilynoted. Once the actual flow is determined, the static pressure rise bythe actual flow can be obtained.

The system resistance curve 33 passing through the performance point 34can be noted by assumption.

In addition, the system resistance curve 33 can be obtained by thefollowing formula. Here, the formula is applied only when the fluid is awarm current.SP=KQ ²

where SP is the static pressure rise, K is a constant, and Q is a volumeflow rate (CFM).

In accordance with the formula, the system resistance curve 33 can beexpressed as a quadratic function. When it is assumed that the systemresistance curve 33 passes through the performance point 34, the curve33 can be represented as shown in FIG. 3.

As the inclination of the system-resistance curve 33 is reduced, theperformance point 34 moves along the fan characteristic curve 31 in adirection where the flow is increased and the static pressure rise isreduced. On the contrary, as the inclination of the system resistancecurve 33 is increased, the performance point 34 moves along the fancharacteristic curve 31 in a direction where the flow is reduced and thestatic pressure rise is increased. That is, the more the static pressurerise is increased, the more the fluid flow resistance is increased,thereby increasing the fluid flow noise.

Therefore, it is preferable to reduce the inclination of the systemresistance curve to reduce the fluid flow noise.

On order to reduce the inclination of the system resistance curve 33, avariety of schemes for (a) properly adjusting a gap between a circuitboard on which heat generating parts are mounted and the cooling fan,(b) properly varying an installation angle of the cooling fan, (c)varying the size of the fluid-through holes of the vent, and (d)properly adjusting a gap between the cooling fan and the back cover, maybe proposed. The present invention relates to the scheme for properlyadjusting the gap between the cooling fan and the back cover.

FIG. 4 shows a graph illustrating fluid flow noise in accordance withthe variation of a gap between the cooling fan and the back cover.

The specification of the cooling fan used for a test is as follows:

Rated Voltage: 12V

Maximum RPM: 1,500 RPM

Maximum Noise: 25 dB.

The test is conducted by operating the cooling fan at 1,100 RPM.

In the graph, the X-axis indicates a gap “b” between the cooling fan 120and the back cover 110, and the Y-axis denotes an overall sound pressurelevel (OSPL).

Describing the test results with reference to the graph, it has beennoted that, when the gap “b” between the cooling fan 120 and the backcover 110 is equal to or more than 8 mm, the system resistance isreduced and the fluid flow noise is minimized.

That is, most of the fluid flow noise is eliminated when the gap “b”between the cooling fan 120 and the back cover 110 is at least 8 mm, andthe OSPL is steeply reduced when the gap “b” is varied from 5 mm to 6mm.

However, it has also been noted that, when the gap “b” is increasedabove 10 mm, an amount of fluid discharged through the vent portion 11is steeply reduced, deteriorating the cooling efficiency. Whenconsidering the above results, it is preferable that the gap “b” betweenthe cooling fan 120 and the back cover 110 is in a range of about 6-10mm.

FIG. 5 shows a graph illustrating fluid flow noise of a variety of fanswith different specifications from each other in accordance with thevariation of a distance between a cooling fan and a back cover.

The specification of the cooling fan to be selected is varied inaccordance with the calorific value of the system. FIG. 5 shows avariation of the OSPL in accordance with the variation of the gapbetween the cooling fan and the back cover of a variety of cooling fanshaving different specifications from each other.

As shown in the graph, although the fluid flow noise is varied inaccordance with a capacity of the cooling fan, the fluid noise curve inaccordance with the variation of the gap “b” appears in an identicalpattern.

That is, even when the specifications of the cooling fans are differentfrom each other, the fluid flow noise is optimally minimized when thegap “b” is in the range of 6-10 mm.

FIG. 6 shows a back cover structure according to a second embodiment ofthe present invention.

As shown in the drawing, the back cover structure of this embodimentcomprises a back cover 110 having a vent portion that is concave outwardaway from the cooling fan such that the vent portion can be formed in adome shape.

Therefore, the cooling fan 120 can be disposed as close as possible tothe base plane of the back cover 110, while maintaining a proper gapwith the vent portion, thereby minimizing the fluid flow noise.

That is, by designing a gap between the cooling fan 120 and a specificportion (the vent) to be in a range of about 6-10 mm, more preferably 8mm, the fluid flow noise can be minimized while not deteriorating theslim characteristic of the system.

Namely, the noise of the system can be reduced while not affecting theaesthetics.

FIG. 7 shows a back cover structure according to a third embodiment ofthe present invention.

As shown in the drawing, a vent portion of the back cover 110 is concaveoutward from the base plane (away from the cooling fan) such that it hasa bow-shaped section.

It has been noted that the flow rate is relatively low at a center ofeach blade of the cooling fan, and it is relatively high at a rotationalcenter or a periphery of the blade. Therefore, this embodiment isdesigned in response to such a characteristic of the flow rate. Thelengths of the arrows in the drawing represent the flow rates.

Furthermore, by designing the back cover with the vent portion havingthe bow-shaped section, the outer appearance of the system is improved,giving a good impression to the users.

FIGS. 8 and 9 show back cover structures according to fourth and fifthembodiment, respectively.

The vent portion 11 is concave outward from a base plane (away from thecooling fan) of the back cover 110 such that it has a square-shapedsection (see FIG. 8). Alternatively, portions of the vent portion 11,which correspond to blades of the cooling fan 120 are concave outwardaway from the cooling fan such that they have a square-shaped section(see FIG. 9).

Meanwhile, when a gap between the cooling fan 120 and the back cover 110is determined, the distance of the gap may be measured from each of theblades. The distance from the back cover 110 may be measured from themost concave portion of the back cover.

The vent portion corresponding to the cooling fan 110 is formed in acircular shape or a donut or rim shape, considering that the cooling fan120 is circular shaped.

As described above, the cover structure of the present invention isdesigned to reduce the fluid flow noise caused by the operation of thecooling fan, thereby preventing malfunctions of the system where thecover structure is employed.

In addition, the appearance of the back cover is improved, providing agood impression to the user.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present invention. Thus,it is intended that the present invention covers the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

1-17. (canceled)
 18. A cover structure with a vent, comprising: acooling fan; and a cover having a vent portion provided with a pluralityof air-through holes through which air forced by the cooling fanescapes, wherein the vent portion is spaced away from the cooling fan bya distance of about 6-10 mm.
 19. The cover structure according to claim18, wherein the distance is measured from a most concave portion of thevent portion to a closest portion of the blade to the cover.
 20. Thecover structure according to claim 18, wherein the vent portioncomprises a concave section that faces the cooling fan.